The mechanisms underlying overtraining syndrome have not been clearly identified, but are likely to involve autonomic dysfunction and possibly increased cytokine production resulting from the physical stress of intense daily training with inadequate recovery. Sourced from: http://www.nature.com/icb/journal/v78/n5/full/icb200070a.html
Research has shown that overtraining syndrome is a neuroendocrine disorder that is characterized by the following characteristics;
Washed-out feeling, tired, drained, lack of energy Mild leg soreness, general aches and pains Pain in muscles and joints Sudden drop in performance Insomnia Headaches Decreased immunity (increased number of colds, and sore throats) Decrease in training capacity / intensity Moodiness and irritability Depression Loss of enthusiasm for the sport Decreased appetite Increased incidence of injuries.
Elevated Resting Heart Rate Stress fractures Over-use injuries Illness, or flu-like symptoms Frequent infection Chronic soreness Loss of body weight Anorexia Obsessive/compulsive behavior with exercise Sourced from: http://www.livefitlean.com/overtraining/
It is important to listen to your body signals and rest when you feel tired. Sourced from: http://sportsmedicine.about.com/cs/overtraining/a/aa062499a.htm